Roofing tiles including shingles have been made from natural materials, including asphalt, wood, slate, quarry tile or a ceramic material, for example. Asphalt shingles require a crushed gravel surface layer to resist erosion due to falling precipitation and water runoff. Pigment on the gravel provide a choice of colors for the asphalt shingles. Tiles made from natural materials tend to be brittle and prone to fracture. Moreover, natural materials, such as, slate and ceramics are heavy, and are unsuitable for use on buildings of light construction or for use in earthquake prone locations. By contrast, synthetic tiles made of a resinous polymeric composition are less brittle and weigh less than slate or ceramics. Chemical additives in the resinous polymeric composition provide desirable properties, such as, flame resistance and weather resistance.
A choice of colors for synthetic tiles can be provided by adding a pigment throughout the resinous polymeric composition. However, the pigment is not required in hidden portions of the tiles. The hidden portions of the tiles reside below the surface, and further where the tiles overlap and cover portions of one another while on a roof. It would be advantageous to conserve pigment consumption by locating the pigment on the tile surface instead of throughout the tile thickness. Further, it would be advantageous to minimize the pigment on the portions of the tiles that are intended to be hidden from view.
A roofing tile made of a natural material has a distinctive coloration pattern that identifies itself as being a particular natural material, for example, a crushed gravel surface layer, wood grain, slate, quarry tile or ceramic material. For example, the natural material has a base color, different shades of the base color, contrasting colors and color streaks A resinous polymeric roofing composition is required to simulate the appearance of a roofing tile made of a natural material, such as, a crushed gravel surface layer, wood, slate, quarry or ceramic material.
Accordingly, it would be advantageous to provide a resinous polymeric roofing composition with an arrangement of one or more surface colors in a coloration pattern that simulates a distinctive variegated surface coloration pattern of a naturally occurring material.
A roofing tile made from a natural material has naturally occurring surface topography features and surface roughness, which are distinctive of the natural material. It would be advantageous for a synthetic roofing tile to simulate the surface topography features and surface roughness of the natural material by impressing such surface topography features and roughness into a surface of a resinous polymeric roofing composition. Further, it would be advantageous for an arrangement of one or more pigment colors in a variegated surface coloration pattern that register with the surface topography features and surface roughness of a natural material being simulated by the synthetic roofing tile.
US 2006/0029775 A1 discloses a single roofing shingle made by coextruding a capstock layer with a filler material, and then cutting the same into one or more individual shingles. U.S. Pat. No. 3,897,667 discloses casting a foam onto a sheet formed into a panel of shingles in a closed mold wherein closing and opening the mold is performed in a step and repeat process.
U.S. Pat. No. 5,167,781 discloses a foamed plastic material injected into a mold cavity while at an early stage of its foaming action. Foaming is completed in the mold to control finished product density. A separate assembly operation is required to join the foamed plastic material with an outer layer to form a panel. It would be advantageous to eliminate the separate assembly operation by an apparatus capable of bonding the foamed plastic layer with the outer layer while the inner layer is foamed and molded to a desired shape.
U.S. Pat. No. 6,641,384 discloses a belt mold apparatus for continuously molding a polymeric material between a pair of continuous belts, each of which continuously rotates in a loop that circumscribes spaced apart rollers. The pair of belts continuously rotate into positions adjacent each other to form a moving mold between the belts. The polymeric material in a melt state is introduced into a front end of the moving mold. The moving mold shapes the polymeric material therein to form a continuous manufactured article. The moving mold travels from front to rear, accompanying the moving belts. While the belts move rearward and then rotate away from each other, the mold opens, which releases the continuous manufactured article, such that the article withdraws from the moving mold in a rearward direction. The mold includes a vacuum manifold that draws a vacuum on the polymeric material in the mold interior, such that air in the mold interior is evacuated and the polymeric material fills the mold interior and is shaped by a vacuum molding process. Each belt is supported against a flat support belt having apertures through which the vacuum is drawn, such that the vacuum draws the belt against the support belt. A suitable support belt and vacuum manifold are disclosed in U.S. Pat. No. 5,906,840.
Each of U.S. Pat. Nos. 6,319,456 and 6,737,008 discloses a two-layer polymeric building product of continuous length that is formed with visibly aesthetic distinctive surface features on a surface of the two-layer building product by using a moving mold formed between a pair of moving belts. The belts loop around rotating rollers and travel continuously in respective loops to continuously rotate into position beside each other and form the moving mold therebetween. The building product is continuously molded lengthwise with lateral edge portions extending continuously lengthwise. Subsequent to completion of the mold, such lateral edge portions are plastically deformed while still hot, by using a mechanical means to shape a butt edge and a nailing edge, respectively. Further, a punch press is used to mechanically punch a series of apertures laterally through the nailing edge of the building product. Insulation is disclosed as being applied by spraying a foamed polyurethane emulsion.